An afro-american kid of 6 years of age presented with abdominal pain, chronic hemolysis and abnormal RBC shape on peripheral smear. Most likely disorder responsible for this condition
Sickle cell disease is caused by a mutation in the beta-globin gene, leading to HbS. When oxygen is low, HbS polymerizes, causing RBCs to become sickle-shaped. This leads to hemolysis and vaso-occlusion. The chronic hemolysis explains the anemia and jaundice, and abdominal pain could be from vaso-occlusive crises.
Other options might be G6PD deficiency, but that's more common in males and presents with acute hemolysis after certain drugs or infections. Thalassemia is more common in Mediterranean or Asian populations. Hereditary spherocytosis causes spherocytes, not sickle cells. So the correct answer is sickle cell disease.
**Core Concept**
This question tests knowledge of inherited hemoglobinopathies causing chronic hemolysis and characteristic red blood cell (RBC) morphology. Sickle cell disease, caused by a mutation in the *β-globin gene* (HBB), leads to sickle-shaped RBCs, vaso-occlusion, and chronic hemolytic anemia, particularly in individuals of African descent.
**Why the Correct Answer is Right**
Sickle cell disease results from a point mutation (GAG → GTG) in the β-globin gene, substituting glutamic acid with valine at position 6 (HbS). Under hypoxic conditions, HbS polymerizes, distorting RBCs into a sickle shape. This causes mechanical hemolysis, vaso-occlusive crises (e.g., abdominal pain), and chronic anemia. Peripheral smear shows sickle cells, target cells, and nucleated RBCs. The presentation aligns with homozygous sickle cell anemia (HbSS), common in Afro-American populations.
**Why Each Wrong Option is Incorrect**
**Option A:** *G6PD deficiency* causes acute hemolytic anemia triggered by drugs/infections, not chronic hemolysis or sickle-shaped RBCs.
**Option B:** *β-thalassemia* presents with microcytic anemia and target cells but not sickle-shaped RBCs; more prevalent in Mediterranean/Asian populations.
**Option C:** *Hereditary spherocytosis* leads to spherical RBCs (spherocytes), not sickle cells, and is more common in Caucasians.
**Clinical Pearl / High-Yield Fact**
Sickle cell disease is diagnosed via hemoglobin electrophoresis (HbS predominant). Remember "ACS" for key features: **A**bdominal pain (vaso-occlusion), **C**hronic anemia, and **S**ickle-shaped RBCs. Acute chest syndrome and splenic sequestration are other critical complications to recognize.
**Correct Answer: C. Sickle cell disease**